Sigma Islands

Sigma Islands is a group of small islands and rocks which lie 5.6 km (3 nmi) north of Eta Island and mark the north limit of the Melchior Islands, in the Palmer Archipelago. The name, derived from the 18th letter of the Greek alphabet, appears to have been first used on a 1946 Argentine government chart following surveys of these islands by Argentine expeditions in 1942 and 1943.

Map of Sigma Islands, Antarctica